Brake light comes on

VICKIR

MEMBER
2004 TOYOTA SEQUOIA
160,000 MILES

Last summer brake light kept coming on but toyota found no problem. For the past month the light has started coming on again. All winter no problem. But when the vehicle sits out in the hot sun, when started the light comes on.

Thursday, August 8th, 2013 AT 7:19 PM

3 Replies

CJ MEDEVAC

MECHANIC
11,005 POSTS

Hello,

This sound sliek the fluid level sensor in the master cylinder is going out. When the light is on can you unplug the sensor to see if the light goes out?

This guide can help

https://www.2carpros.com/articles/brake-system-warning-light-on

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Thursday, August 8th, 2013 AT 8:06 PM

VICKIR

MEMBER
2 POSTS

Yes. This all started last summer after I had the oil changed. Toyota changed the brake computer and a week later same problem again. Then toyota wanted to change master booster cylinder and I could not afford that. Well then the problem stopped. Even took it to another Toyota place and then ran the diagnostics on it and said there was no codes so it was ok. Then the first of July it was sitting in the hot sun all day while I work. Has come on 4 times in last 30 days. Each time after sitting in sun. So I unplugged the sensor and the light when off should I get a new sensor?

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Friday, August 9th, 2013 AT 8:20 AM

CJ MEDEVAC

MECHANIC
11,005 POSTS

On other vehicles, I have seen the float inside the brake fluid reservoir get stuck when the fluid got low (then refilled). Or they bounced it around a bit

the float/ magnet would sorta get cocked a little bit in the tracks that it traveled in

sticking your finger in the fill hole would generally dis-lodge it

not knowing how heat might affect it.

Before you do anything. Can you see the float's position?

Maybe it's stuck, and on the "verge" of turning the switch on. The heat (expansion) is pushing it over the edge?

Maybe your float sinks when it gets hot?

Does unplugging the reservoir turn it off. Or is something else in the system turning it on?

The medic

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